The invention relates to an adjusting apparatus, particularly for an internal combustion engine having a housing with cylinders, pistons movably disposed in the cylinders by a crankshaft rotatably supported in the housing and connected to the pistons by piston rods and also to a method for operating an adjusting apparatus for such an internal combustion engine.
EP 1 307 642 B1 discloses a reciprocating-piston internal combustion engine with a variable compression ratio, in which a transverse lever is arranged between a connecting rod and the crankshaft and is itself supported by a secondary connecting rod. Furthermore, this secondary connecting rod is connected to an eccentric shaft via an eccentric. As a result of the rotation of the eccentric shaft and of the eccentric arranged on it, the secondary connecting rod is moved. The connecting rod and a piston fastened to it are thereby displaced by the transverse lever, whereby the compression ratio is changed. An adjustment of the eccentric shaft takes place by means of a separately switched motor or via a gear from the crankshaft of the internal combustion engine. During adjustment, depending on the position of the piston and of the connecting rod, considerable forces are to be overcome in order to adjust the entire active chain of mechanical transmission elements counter to the combustion pressure in the most unfavorable case. A similar problem arises with regard to actuating elements for controlling the gas exchange valves, within the active chain of which a fluctuating load likewise occurs. Here too, in the most unfavorable case, an adjustment of the profile of the valve lift counter to the overall spring force of the valve spring, plus, in addition, possible mass forces arising from the valve movement, is required.
It is the object of the present invention to provide an apparatus which, at low outlay in terms of energy, makes it possible to adjust a fluctuatingly stressed active chain of mechanical transmission elements.